1. Field of the Invention
The present invention relates to an organic light emitting diode (OLED) display. More particularly, it relates to an OLED display having improved display characteristics.
2. Description of the Related Art
An OLED display includes a plurality of organic light emitting diodes (OLEDs). OLEDs typically include hole injection electrodes, an organic light emission layer, and electron injection electrodes. Light is emitted when excitons are generated in the organic light emission layer. Excitons are generated as electrons and holes are combined drop from an excited state to a ground state. The OLED display displays an image by using the light resulting from these excitons.
Accordingly, the OLED display has self-luminance characteristics, and unlike a liquid crystal display (LCD), the thickness and weight thereof can be reduced since a separate light source is not required. Thus, OLED displays are used in various applications, such as displays in mobile electronic devices, because an OLED display has low power consumption, high luminance, and high reaction speed.
Unfortunately, one of the electrodes and other metal wires in the OLED display can reflect external light, such as ambient light. This reflected light can deteriorate the performance of the OLED display, especially when the OLED display is used in a bright setting. For example, the OLED display's expression of black color and contrast can be deteriorated due to reflections of external light, thereby reducing visibility of the OLED display.
One known technique for solving this problem is the use of a polarizing plate and a phase delay plate. These plates are arranged on an OLED for suppressing reflection of external light. However, because light from the organic emission layer must pass through them, the polarizing plate and phase delay plate also reduce the light generated from the OLED and may decrease the performance and visibility of the OLED display device.
The above information disclosed in this Background section is only for enhancement of understanding. Therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.